In 2014, there was a surge in unaccompanied children at the United States-Mexico border — 80,000 children, including infants and toddlers, were detained in less than a year, most of them from Central America. They had traveled on trails littered with human remains, evading ranchers who had taken to hunting migrants for sport. By some estimates, 80 percent of the girls and women had been raped as they passed through Mexico. Countless others died or vanished along the way.

The Mexican-born novelist Valeria Luiselli closely followed this news, struck by how the language used to describe the children — illegals, aliens — so efficiently dehumanized them. Many were fleeing gang violence in Guatemala, El Salvador and Honduras. Luiselli wondered why no one called them refugees—or even just children. She began volunteering as a court interpreter, helping the children with the intake questionnaire that might establish a case for asylum, and has since written two books inspired by that work.

In “Tell Me How It Ends: An Essay in 40 Questions” (2017), she interspersed the experiences of the children with her own, as she applied for a green card. “Lost Children Archive,” her much-anticipated new novel, and her first written in English, stages the questions she had only posed in her previous book: How best to draw attention to the refugee children — and is it even her story to tell? Is it ever defensible to make art out of someone else’s suffering? If so, how on earth to keep it from turning pious and dully moralizing?

These are the signal concerns of much contemporary fiction, as Western writers have begun cautiously responding to the refugee crisis, typically with careful and complex fictional portraits of migrant characters: see Donal Ryan’s “From a Low and Quiet Sea,” Lisa Halliday’s “Asymmetry,” Jenny Erpenbeck’s “Go, Went, Gone.”

The typical way is not the Luiselli way. The author of three cheerfully wayward novels and one essay collection, her imagination is keen and uninhibited. Each project has been its own experiment — a palimpsest of texts (“Sidewalks”) or a collaboration with readers in serial format (“The Story of My Teeth”). The novel truly becomes novel again in her hands — electric, elastic, alluring, new. And the story of the migrant, she believes, insists upon a new form: How else to tell a story that has no end?

“Lost Children Archive” begins with a journey — not of a fictional migrant but of an unhappily married couple. The narrator and her husband were both single parents when they met while working on a project cataloging the sounds of New York. “We fell in love,” the narrator says, “completely, irrationally, predictably and headfirst, like a rock might fall in love with a bird, not knowing who the rock was and who the bird.”

She finds out soon enough. Her husband turns distant, and she watches him hungrily, mourning him as if he is already gone — “the process, both meticulous and intuitive, by which he makes coffee in the mornings, makes sound pieces, and sometimes makes love to me.” When he plans a new project, to travel to the ancestral homeland of the Apaches in Arizona, she fastens herself to him. She will record the sounds at the border and also search for the undocumented daughters of a friend, who have gone missing. (The real-life inspiration for this story appeared in “Tell Me How It Ends” — two young Guatemalan sisters make the journey across the border with the phone number of their mother in Long Island stitched into the collars of their dresses.)

“Lost Children Archive” is a retelling of the American road novel, with a twist. In this version, there is no flight from the domestic — the journey has been taken to save a marriage, and the squalling children are in tow. Luiselli is a superb chronicler of children, and the narrator’s 5-year-old daughter and her husband’s 10-year-old son feel piercingly real — perceptive, irreplaceable, wonderfully odd. “Imagine the first person who ever milked a cow,” the boy wonders out loud, to no one in particular. “What a strange person.”

The novel is organized around the boxes each family member carries along on the trip. They overflow with newspaper clippings and snapshots, research materials and nested narratives about lost children, real and invented; histories of the Apaches and of kudzu. The book becomes an archive — of curiosities, yearnings, of the life of a new, fragile, fracturing family, animated by the narrator’s restless energy as she churns over a way to tell the story of the refugee children.

Her own children come to her aid. She notices that they refer to the refugee children, many of whom go missing, as “the lost children.” She adopts the term: “They are children who have lost the right to a childhood.” We see her start to understand how language can be used as an agent of violence and repair. We see her searching for a form — and then, suddenly, as if to illustrate how such a form might be possible, the book breaks out of the meandering rhythms of the road trip and into a a heart-stopping 20-page, single-sentence climax.

The narrator’s own children go missing. They run away, reasoning, “Ma would start thinking of us the way she thought of them, the lost children. All the time and with all her heart. And Pa would focus on finding our echoes, instead of all the other echoes he was chasing.” In this way, by visiting the terrors that refugee children routinely face upon these children — our children, as they have come to feel in the novel; children expected to be spared — Luiselli drives home just how much pain and sacrifice we are prepared to accept in the lives of others. She dramatizes what it takes for people to stare hard at their own families, to examine their complicity in other people’s suffering.

To call these morals or messages does a disservice to the novel’s rangy storytelling and panoptic curiosity. Better to think of it as a challenge.

As the narrator once tells the boy: “Look hard and tell me everything. We are all counting on you.”